| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * INET An implementation of the TCP/IP protocol suite for the LINUX |
| * operating system. INET is implemented using the BSD Socket |
| * interface as the means of communication with the user level. |
| * |
| * Definitions for the TCP protocol. |
| * |
| * Version: @(#)tcp.h 1.0.2 04/28/93 |
| * |
| * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
| */ |
| #ifndef _LINUX_TCP_H |
| #define _LINUX_TCP_H |
| |
| |
| #include <linux/skbuff.h> |
| #include <linux/win_minmax.h> |
| #include <net/sock.h> |
| #include <net/inet_connection_sock.h> |
| #include <net/inet_timewait_sock.h> |
| #include <uapi/linux/tcp.h> |
| |
| static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb) |
| { |
| return (struct tcphdr *)skb_transport_header(skb); |
| } |
| |
| static inline unsigned int __tcp_hdrlen(const struct tcphdr *th) |
| { |
| return th->doff * 4; |
| } |
| |
| static inline unsigned int tcp_hdrlen(const struct sk_buff *skb) |
| { |
| return __tcp_hdrlen(tcp_hdr(skb)); |
| } |
| |
| static inline struct tcphdr *inner_tcp_hdr(const struct sk_buff *skb) |
| { |
| return (struct tcphdr *)skb_inner_transport_header(skb); |
| } |
| |
| static inline unsigned int inner_tcp_hdrlen(const struct sk_buff *skb) |
| { |
| return inner_tcp_hdr(skb)->doff * 4; |
| } |
| |
| static inline unsigned int tcp_optlen(const struct sk_buff *skb) |
| { |
| return (tcp_hdr(skb)->doff - 5) * 4; |
| } |
| |
| /* TCP Fast Open */ |
| #define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */ |
| #define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */ |
| #define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */ |
| |
| /* TCP Fast Open Cookie as stored in memory */ |
| struct tcp_fastopen_cookie { |
| __le64 val[DIV_ROUND_UP(TCP_FASTOPEN_COOKIE_MAX, sizeof(u64))]; |
| s8 len; |
| bool exp; /* In RFC6994 experimental option format */ |
| }; |
| |
| /* This defines a selective acknowledgement block. */ |
| struct tcp_sack_block_wire { |
| __be32 start_seq; |
| __be32 end_seq; |
| }; |
| |
| struct tcp_sack_block { |
| u32 start_seq; |
| u32 end_seq; |
| }; |
| |
| /*These are used to set the sack_ok field in struct tcp_options_received */ |
| #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */ |
| #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ |
| |
| struct tcp_options_received { |
| /* PAWS/RTTM data */ |
| int ts_recent_stamp;/* Time we stored ts_recent (for aging) */ |
| u32 ts_recent; /* Time stamp to echo next */ |
| u32 rcv_tsval; /* Time stamp value */ |
| u32 rcv_tsecr; /* Time stamp echo reply */ |
| u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ |
| tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ |
| dsack : 1, /* D-SACK is scheduled */ |
| wscale_ok : 1, /* Wscale seen on SYN packet */ |
| sack_ok : 3, /* SACK seen on SYN packet */ |
| smc_ok : 1, /* SMC seen on SYN packet */ |
| snd_wscale : 4, /* Window scaling received from sender */ |
| rcv_wscale : 4; /* Window scaling to send to receiver */ |
| u8 saw_unknown:1, /* Received unknown option */ |
| unused:7; |
| u8 num_sacks; /* Number of SACK blocks */ |
| u16 user_mss; /* mss requested by user in ioctl */ |
| u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ |
| }; |
| |
| static inline void tcp_clear_options(struct tcp_options_received *rx_opt) |
| { |
| rx_opt->tstamp_ok = rx_opt->sack_ok = 0; |
| rx_opt->wscale_ok = rx_opt->snd_wscale = 0; |
| #if IS_ENABLED(CONFIG_SMC) |
| rx_opt->smc_ok = 0; |
| #endif |
| } |
| |
| /* This is the max number of SACKS that we'll generate and process. It's safe |
| * to increase this, although since: |
| * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) |
| * only four options will fit in a standard TCP header */ |
| #define TCP_NUM_SACKS 4 |
| |
| struct tcp_request_sock_ops; |
| |
| struct tcp_request_sock { |
| struct inet_request_sock req; |
| const struct tcp_request_sock_ops *af_specific; |
| u64 snt_synack; /* first SYNACK sent time */ |
| bool tfo_listener; |
| bool is_mptcp; |
| #if IS_ENABLED(CONFIG_MPTCP) |
| bool drop_req; |
| #endif |
| u32 txhash; |
| u32 rcv_isn; |
| u32 snt_isn; |
| u32 ts_off; |
| u32 last_oow_ack_time; /* last SYNACK */ |
| u32 rcv_nxt; /* the ack # by SYNACK. For |
| * FastOpen it's the seq# |
| * after data-in-SYN. |
| */ |
| u8 syn_tos; |
| }; |
| |
| static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) |
| { |
| return (struct tcp_request_sock *)req; |
| } |
| |
| struct tcp_sock { |
| /* inet_connection_sock has to be the first member of tcp_sock */ |
| struct inet_connection_sock inet_conn; |
| u16 tcp_header_len; /* Bytes of tcp header to send */ |
| u16 gso_segs; /* Max number of segs per GSO packet */ |
| |
| /* |
| * Header prediction flags |
| * 0x5?10 << 16 + snd_wnd in net byte order |
| */ |
| __be32 pred_flags; |
| |
| /* |
| * RFC793 variables by their proper names. This means you can |
| * read the code and the spec side by side (and laugh ...) |
| * See RFC793 and RFC1122. The RFC writes these in capitals. |
| */ |
| u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived |
| * sum(delta(rcv_nxt)), or how many bytes |
| * were acked. |
| */ |
| u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn |
| * total number of segments in. |
| */ |
| u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn |
| * total number of data segments in. |
| */ |
| u32 rcv_nxt; /* What we want to receive next */ |
| u32 copied_seq; /* Head of yet unread data */ |
| u32 rcv_wup; /* rcv_nxt on last window update sent */ |
| u32 snd_nxt; /* Next sequence we send */ |
| u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut |
| * The total number of segments sent. |
| */ |
| u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut |
| * total number of data segments sent. |
| */ |
| u64 bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut |
| * total number of data bytes sent. |
| */ |
| u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked |
| * sum(delta(snd_una)), or how many bytes |
| * were acked. |
| */ |
| u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups |
| * total number of DSACK blocks received |
| */ |
| u32 snd_una; /* First byte we want an ack for */ |
| u32 snd_sml; /* Last byte of the most recently transmitted small packet */ |
| u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ |
| u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ |
| u32 last_oow_ack_time; /* timestamp of last out-of-window ACK */ |
| u32 compressed_ack_rcv_nxt; |
| |
| u32 tsoffset; /* timestamp offset */ |
| |
| struct list_head tsq_node; /* anchor in tsq_tasklet.head list */ |
| struct list_head tsorted_sent_queue; /* time-sorted sent but un-SACKed skbs */ |
| |
| u32 snd_wl1; /* Sequence for window update */ |
| u32 snd_wnd; /* The window we expect to receive */ |
| u32 max_window; /* Maximal window ever seen from peer */ |
| u32 mss_cache; /* Cached effective mss, not including SACKS */ |
| |
| u32 window_clamp; /* Maximal window to advertise */ |
| u32 rcv_ssthresh; /* Current window clamp */ |
| |
| /* Information of the most recently (s)acked skb */ |
| struct tcp_rack { |
| u64 mstamp; /* (Re)sent time of the skb */ |
| u32 rtt_us; /* Associated RTT */ |
| u32 end_seq; /* Ending TCP sequence of the skb */ |
| u32 last_delivered; /* tp->delivered at last reo_wnd adj */ |
| u8 reo_wnd_steps; /* Allowed reordering window */ |
| #define TCP_RACK_RECOVERY_THRESH 16 |
| u8 reo_wnd_persist:5, /* No. of recovery since last adj */ |
| dsack_seen:1, /* Whether DSACK seen after last adj */ |
| advanced:1; /* mstamp advanced since last lost marking */ |
| } rack; |
| u16 advmss; /* Advertised MSS */ |
| u8 compressed_ack; |
| u8 dup_ack_counter:2, |
| tlp_retrans:1, /* TLP is a retransmission */ |
| unused:5; |
| u32 chrono_start; /* Start time in jiffies of a TCP chrono */ |
| u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */ |
| u8 chrono_type:2, /* current chronograph type */ |
| rate_app_limited:1, /* rate_{delivered,interval_us} limited? */ |
| fastopen_connect:1, /* FASTOPEN_CONNECT sockopt */ |
| fastopen_no_cookie:1, /* Allow send/recv SYN+data without a cookie */ |
| is_sack_reneg:1, /* in recovery from loss with SACK reneg? */ |
| fastopen_client_fail:2; /* reason why fastopen failed */ |
| u8 nonagle : 4,/* Disable Nagle algorithm? */ |
| thin_lto : 1,/* Use linear timeouts for thin streams */ |
| recvmsg_inq : 1,/* Indicate # of bytes in queue upon recvmsg */ |
| repair : 1, |
| frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */ |
| u8 repair_queue; |
| u8 save_syn:2, /* Save headers of SYN packet */ |
| syn_data:1, /* SYN includes data */ |
| syn_fastopen:1, /* SYN includes Fast Open option */ |
| syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */ |
| syn_fastopen_ch:1, /* Active TFO re-enabling probe */ |
| syn_data_acked:1,/* data in SYN is acked by SYN-ACK */ |
| is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */ |
| u32 tlp_high_seq; /* snd_nxt at the time of TLP */ |
| |
| u32 tcp_tx_delay; /* delay (in usec) added to TX packets */ |
| u64 tcp_wstamp_ns; /* departure time for next sent data packet */ |
| u64 tcp_clock_cache; /* cache last tcp_clock_ns() (see tcp_mstamp_refresh()) */ |
| |
| /* RTT measurement */ |
| u64 tcp_mstamp; /* most recent packet received/sent */ |
| u32 srtt_us; /* smoothed round trip time << 3 in usecs */ |
| u32 mdev_us; /* medium deviation */ |
| u32 mdev_max_us; /* maximal mdev for the last rtt period */ |
| u32 rttvar_us; /* smoothed mdev_max */ |
| u32 rtt_seq; /* sequence number to update rttvar */ |
| struct minmax rtt_min; |
| |
| u32 packets_out; /* Packets which are "in flight" */ |
| u32 retrans_out; /* Retransmitted packets out */ |
| u32 max_packets_out; /* max packets_out in last window */ |
| u32 max_packets_seq; /* right edge of max_packets_out flight */ |
| |
| u16 urg_data; /* Saved octet of OOB data and control flags */ |
| u8 ecn_flags; /* ECN status bits. */ |
| u8 keepalive_probes; /* num of allowed keep alive probes */ |
| u32 reordering; /* Packet reordering metric. */ |
| u32 reord_seen; /* number of data packet reordering events */ |
| u32 snd_up; /* Urgent pointer */ |
| |
| /* |
| * Options received (usually on last packet, some only on SYN packets). |
| */ |
| struct tcp_options_received rx_opt; |
| |
| /* |
| * Slow start and congestion control (see also Nagle, and Karn & Partridge) |
| */ |
| u32 snd_ssthresh; /* Slow start size threshold */ |
| u32 snd_cwnd; /* Sending congestion window */ |
| u32 snd_cwnd_cnt; /* Linear increase counter */ |
| u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ |
| u32 snd_cwnd_used; |
| u32 snd_cwnd_stamp; |
| u32 prior_cwnd; /* cwnd right before starting loss recovery */ |
| u32 prr_delivered; /* Number of newly delivered packets to |
| * receiver in Recovery. */ |
| u32 prr_out; /* Total number of pkts sent during Recovery. */ |
| u32 delivered; /* Total data packets delivered incl. rexmits */ |
| u32 delivered_ce; /* Like the above but only ECE marked packets */ |
| u32 lost; /* Total data packets lost incl. rexmits */ |
| u32 app_limited; /* limited until "delivered" reaches this val */ |
| u64 first_tx_mstamp; /* start of window send phase */ |
| u64 delivered_mstamp; /* time we reached "delivered" */ |
| u32 rate_delivered; /* saved rate sample: packets delivered */ |
| u32 rate_interval_us; /* saved rate sample: time elapsed */ |
| |
| u32 rcv_wnd; /* Current receiver window */ |
| u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ |
| u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */ |
| u32 pushed_seq; /* Last pushed seq, required to talk to windows */ |
| u32 lost_out; /* Lost packets */ |
| u32 sacked_out; /* SACK'd packets */ |
| |
| struct hrtimer pacing_timer; |
| struct hrtimer compressed_ack_timer; |
| |
| /* from STCP, retrans queue hinting */ |
| struct sk_buff* lost_skb_hint; |
| struct sk_buff *retransmit_skb_hint; |
| |
| /* OOO segments go in this rbtree. Socket lock must be held. */ |
| struct rb_root out_of_order_queue; |
| struct sk_buff *ooo_last_skb; /* cache rb_last(out_of_order_queue) */ |
| |
| /* SACKs data, these 2 need to be together (see tcp_options_write) */ |
| struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ |
| struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ |
| |
| struct tcp_sack_block recv_sack_cache[4]; |
| |
| struct sk_buff *highest_sack; /* skb just after the highest |
| * skb with SACKed bit set |
| * (validity guaranteed only if |
| * sacked_out > 0) |
| */ |
| |
| int lost_cnt_hint; |
| |
| u32 prior_ssthresh; /* ssthresh saved at recovery start */ |
| u32 high_seq; /* snd_nxt at onset of congestion */ |
| |
| u32 retrans_stamp; /* Timestamp of the last retransmit, |
| * also used in SYN-SENT to remember stamp of |
| * the first SYN. */ |
| u32 undo_marker; /* snd_una upon a new recovery episode. */ |
| int undo_retrans; /* number of undoable retransmissions. */ |
| u64 bytes_retrans; /* RFC4898 tcpEStatsPerfOctetsRetrans |
| * Total data bytes retransmitted |
| */ |
| u32 total_retrans; /* Total retransmits for entire connection */ |
| |
| u32 urg_seq; /* Seq of received urgent pointer */ |
| unsigned int keepalive_time; /* time before keep alive takes place */ |
| unsigned int keepalive_intvl; /* time interval between keep alive probes */ |
| |
| int linger2; |
| |
| |
| /* Sock_ops bpf program related variables */ |
| #ifdef CONFIG_BPF |
| u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs |
| * values defined in uapi/linux/tcp.h |
| */ |
| #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG) |
| #else |
| #define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0 |
| #endif |
| |
| u16 timeout_rehash; /* Timeout-triggered rehash attempts */ |
| |
| u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */ |
| |
| /* Receiver side RTT estimation */ |
| u32 rcv_rtt_last_tsecr; |
| struct { |
| u32 rtt_us; |
| u32 seq; |
| u64 time; |
| } rcv_rtt_est; |
| |
| /* Receiver queue space */ |
| struct { |
| u32 space; |
| u32 seq; |
| u64 time; |
| } rcvq_space; |
| |
| /* TCP-specific MTU probe information. */ |
| struct { |
| u32 probe_seq_start; |
| u32 probe_seq_end; |
| } mtu_probe; |
| u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG |
| * while socket was owned by user. |
| */ |
| #if IS_ENABLED(CONFIG_MPTCP) |
| bool is_mptcp; |
| #endif |
| #if IS_ENABLED(CONFIG_SMC) |
| bool syn_smc; /* SYN includes SMC */ |
| #endif |
| |
| #ifdef CONFIG_TCP_MD5SIG |
| /* TCP AF-Specific parts; only used by MD5 Signature support so far */ |
| const struct tcp_sock_af_ops *af_specific; |
| |
| /* TCP MD5 Signature Option information */ |
| struct tcp_md5sig_info __rcu *md5sig_info; |
| #endif |
| |
| /* TCP fastopen related information */ |
| struct tcp_fastopen_request *fastopen_req; |
| /* fastopen_rsk points to request_sock that resulted in this big |
| * socket. Used to retransmit SYNACKs etc. |
| */ |
| struct request_sock __rcu *fastopen_rsk; |
| struct saved_syn *saved_syn; |
| }; |
| |
| enum tsq_enum { |
| TSQ_THROTTLED, |
| TSQ_QUEUED, |
| TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */ |
| TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */ |
| TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */ |
| TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call |
| * tcp_v{4|6}_mtu_reduced() |
| */ |
| }; |
| |
| enum tsq_flags { |
| TSQF_THROTTLED = (1UL << TSQ_THROTTLED), |
| TSQF_QUEUED = (1UL << TSQ_QUEUED), |
| TCPF_TSQ_DEFERRED = (1UL << TCP_TSQ_DEFERRED), |
| TCPF_WRITE_TIMER_DEFERRED = (1UL << TCP_WRITE_TIMER_DEFERRED), |
| TCPF_DELACK_TIMER_DEFERRED = (1UL << TCP_DELACK_TIMER_DEFERRED), |
| TCPF_MTU_REDUCED_DEFERRED = (1UL << TCP_MTU_REDUCED_DEFERRED), |
| }; |
| |
| static inline struct tcp_sock *tcp_sk(const struct sock *sk) |
| { |
| return (struct tcp_sock *)sk; |
| } |
| |
| struct tcp_timewait_sock { |
| struct inet_timewait_sock tw_sk; |
| #define tw_rcv_nxt tw_sk.__tw_common.skc_tw_rcv_nxt |
| #define tw_snd_nxt tw_sk.__tw_common.skc_tw_snd_nxt |
| u32 tw_rcv_wnd; |
| u32 tw_ts_offset; |
| u32 tw_ts_recent; |
| |
| /* The time we sent the last out-of-window ACK: */ |
| u32 tw_last_oow_ack_time; |
| |
| int tw_ts_recent_stamp; |
| u32 tw_tx_delay; |
| #ifdef CONFIG_TCP_MD5SIG |
| struct tcp_md5sig_key *tw_md5_key; |
| #endif |
| }; |
| |
| static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) |
| { |
| return (struct tcp_timewait_sock *)sk; |
| } |
| |
| static inline bool tcp_passive_fastopen(const struct sock *sk) |
| { |
| return sk->sk_state == TCP_SYN_RECV && |
| rcu_access_pointer(tcp_sk(sk)->fastopen_rsk) != NULL; |
| } |
| |
| static inline void fastopen_queue_tune(struct sock *sk, int backlog) |
| { |
| struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; |
| int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn); |
| |
| queue->fastopenq.max_qlen = min_t(unsigned int, backlog, somaxconn); |
| } |
| |
| static inline void tcp_move_syn(struct tcp_sock *tp, |
| struct request_sock *req) |
| { |
| tp->saved_syn = req->saved_syn; |
| req->saved_syn = NULL; |
| } |
| |
| static inline void tcp_saved_syn_free(struct tcp_sock *tp) |
| { |
| kfree(tp->saved_syn); |
| tp->saved_syn = NULL; |
| } |
| |
| static inline u32 tcp_saved_syn_len(const struct saved_syn *saved_syn) |
| { |
| return saved_syn->mac_hdrlen + saved_syn->network_hdrlen + |
| saved_syn->tcp_hdrlen; |
| } |
| |
| struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, |
| const struct sk_buff *orig_skb, |
| const struct sk_buff *ack_skb); |
| |
| static inline u16 tcp_mss_clamp(const struct tcp_sock *tp, u16 mss) |
| { |
| /* We use READ_ONCE() here because socket might not be locked. |
| * This happens for listeners. |
| */ |
| u16 user_mss = READ_ONCE(tp->rx_opt.user_mss); |
| |
| return (user_mss && user_mss < mss) ? user_mss : mss; |
| } |
| |
| int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount, |
| int shiftlen); |
| |
| void tcp_sock_set_cork(struct sock *sk, bool on); |
| int tcp_sock_set_keepcnt(struct sock *sk, int val); |
| int tcp_sock_set_keepidle_locked(struct sock *sk, int val); |
| int tcp_sock_set_keepidle(struct sock *sk, int val); |
| int tcp_sock_set_keepintvl(struct sock *sk, int val); |
| void tcp_sock_set_nodelay(struct sock *sk); |
| void tcp_sock_set_quickack(struct sock *sk, int val); |
| int tcp_sock_set_syncnt(struct sock *sk, int val); |
| void tcp_sock_set_user_timeout(struct sock *sk, u32 val); |
| |
| #endif /* _LINUX_TCP_H */ |